Multi-line telephone with input/output mixing and audio control

ABSTRACT

The present invention is a method and apparatus for selectively controlling the interconnectivity of two or more active telephone lines and/or one or more audio characteristics of each of the active telephone liens during a multi-line call. A bridge or a call connection control may be implemented to provide selective call connection for each active telephone call. The user may thereby control the interconnectivity of each parry to the user and to the other parties to the conference or multi-line call. An audio controller may also be implemented within a multi-line telephone or at a telephony switch. The call connection control or the volume control may be implemented within the telephone network such as a switch or locally at the telephone unit. The user may provide the desired interconnectivity or volume parameters for the multi party call using a user interface. Optionally, the audio controller may process the audio signals of the conferenced telephone lines and intelligently adjust the audio characteristics of the audio signals.

[0001] This patent application is a divisional of U.S. patentapplication Ser. No. 09/268,538, filed Mar. 15, 1999, for which priorityis claimed. The parent application is incorporated herein by referencein its entirety. The parent application claims the benefit of U.S.Provisional Application No. 60/114,555 filed on Dec. 31, 1998.

FIELD OF THE INVENTION

[0002] The present invention relates to telephone systems providingmultiple party calling and more particularly to a multi-line callingtelephone system capable of selectively controlling theinterconnectivity and audio characteristics of each individual activetelephone line.

BACKGROUND OF THE INVENTION

[0003] Conference and multi-person calling have become increasinglypopular and common calling techniques for businesses as well asindividual subscribers. These multi-line calling techniques allowmultiple callers to be connected to each other thereby allowing thecallers to communicate with each other. The user may couple two or moretelephone lines such that the user and the parties associated with therespective telephone lines may communicate with each other in aconference call. Alternatively, the user may place multiple calls andcommunicate with each of the called parties without allowing the calledparties to communicate with each other. A telephone party may beconferenced or simultaneously coupled to multiple parties within amulti-line telephone or even an ordinary telephone. In a multi-linetelephone, a plurality of telephone lines may be coupled to a singlemulti-line telephone unit. The user may select the particular telephoneline from which to place a call or the particular line to answer anincoming call; alternatively, the multi-line telephone may automaticallyselect the lines.

[0004] The multiple party calling concept may also be implemented withinmulti-media communication systems. For example, U.S. Pat. No. 5,195,086discloses a multiple call control method in a multimedia conferencingsystem where each call may comprise one or more channels. Such systemsallow multiple parties to communicate over voice, video and data lines.

[0005] These conferencing and multi-line systems, however, are limitingin a variety of respects. For instance, these systems have a limitedability to control the interconnectivity between the parties in amulti-party call. As a result, these systems cannot handle a number offunctions that the calling party may seek in a multi-line telephonesystem. For example, in the case where a calling party is conferencedwith one or more conferenced parties, the calling party may seek toconference in a secret advisor to the call such that the secret advisormay hear the entire conversation, and advise the calling party withoutthe secret advisor being heard by the other conferenced parties.Alternatively, if the calling party is on hold by the first calledparty, the calling party may seek to place other calls while on holdwhile not having the two calls conferenced together, yet continue tolisten to the held call. The calling party may wish to independentlymonitor the line in which he/she is on hold while engaging in adiscussion with the other called parties. In yet another example, thecalling party may seek to make a plurality of non-conferenced calls andbroadcast one or more messages, or simultaneously listen to all of theparties. Present systems are unable to provide the user with these andother such finer call control features that can greatly enhance thefunctionality of the system

[0006] The conferencing and multi-line systems of the prior art are alsolimiting in that they are unable to control one or more audiocharacteristics of each individual line. Often, during a conferencecall, one party is calling through a bad telephone connection or theparty is using a weak telephone receiver. This affects the conferencecall as this party is barely heard by the other parties to theconference call. Further, in the case of a half-duplex conferencingsystem, the party having the bad connection may not be able to interruptwhen others are talking or even if there is background noise.Alternatively, where a party's line has a lot of noise (such as in thecase where the party is using a cellular phone), it may be desirable toreduce the volume or noise level from that party. In other callconferencing situations, the user may desire that the volume of one linebe different than that of another line and also to re-adjust theconnection mode. For example, in the case where the user is on hold on afirst line and that line is playing background music, the calling partymay wish to decrease the volume of that line while he/she continuesdiscussions with another conferenced party on a second line. When theparty from the first line returns, the calling party may then wish tore-adjust the volume of the first line relative to the second line.Telephone sets generally have volume control but this control merelyadjusts the overall volume output from the telephone speaker. Suchtelephone sets are incapable of selectively distinguishing between thetelephone lines to control the relative volume of each individual lineor other audio characteristics of the line such as noise, bass, treble,etc.

[0007] Consequently, there remains a need in the art to provide amulti-line telephone system capable of providing enhancedinterconnectivity control and selective control of one or more audiocharacteristics for each of the active telephone lines.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to solving these and otherproblems and disadvantages of the prior art. The present invention is amethod and apparatus for selectively controlling the interconnectivityand one or more audio characteristics of one or more active telephonelines during a conference or multi-line call. A bridge or a callconnection control may be implemented to provide selective callconnection for each telephone call. The user may thereby control theinterconnectivity of each party to the user and to the other parties tothe conference or multi-line call. An audio controller may also beimplemented within a multi-line telephone or at a telephony switch. Thecall connection control or the audio control may be implemented withinthe telephone network such as a switch or locally at the telephone unit.The user may provide the desired interconnectivity or audio parametersfor the multi party call using a user interface. Optionally, the audiocontroller may process the audio signals of the conferenced telephonelines and intelligently adjust one or more audio characteristics of theaudio signals.

[0009] Further details and features of the present invention may beunderstood from a careful reading of the detailed description thereofwhich follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a schematic diagram of a multi-line telephone system inaccordance with a preferred embodiment of the present invention asimplemented within a communications network;

[0011]FIG. 2 is a schematic diagram of a multi-line telephone systemimplemented within a communications network in accordance with anotherpreferred embodiment of the present invention;

[0012]FIG. 3 shows a preferred embodiment of a user interface of amulti-line telephone system in accordance with the present invention;

[0013]FIG. 4 shows another preferred embodiment of a user interface of amulti-line telephone system in accordance with the present invention;

[0014]FIG. 5 is a schematic block diagram of a telephone system inaccordance with the present invention; and

[0015] FIGS. 6-12 are illustrations of exemplary multi-line callconnections that may be made in accordance with the present invention.

DETAILED DESCRIPTION

[0016]FIG. 1 is a schematic diagram of a multi-line telephone system 105in accordance with a preferred embodiment of the present invention asimplemented within a communications network. The multi-line telephonesystem 105 includes a multi-line telephone 110 coupled to one or moretelephone lines 121 and 122. The multi-line telephone 110 may have twoor more telephone lines which may be separate telephone lines or may befewer lines that are multiplexed to provide functionality for a greaternumber of telephone lines. The multi-line telephone system furtherincludes an audio controller 115 (discussed in further detail herein)for each of the telephone lines 121 and 122 associated with multi-linetelephone 110. Multi-line telephone system 105 is coupled to a centraloffice 120 of a standard public telephony network 125. Other oradditional switching systems may be utilized to couple multi-linetelephone 110 to network 125, including, but not limited to, a PrivateBranch Exchange (PBX). Multi-line telephone system 105 is capable ofplacing calls to or receiving calls from two or more calling parties attelephones 130 and 135 and conferencing the two or more calls. Aconference call allows a user at multi-line telephone 110 and parties attelephone 130 and 135 to communicate with each other. Typically, thethree conferenced parties communicate with each other by voice or audiosignals. Multi-line telephone system 105 may be implemented within amulti-media system capable of audio, video and data communications. Inthis case, a conference call allows the conferenced parties tocommunicate by audio, video and data signals.

[0017] Advantageously, in accordance with this embodiment of the presentinvention, multi-line telephone system 105 includes one or more audiocontrollers 115 that allow the user to selectively adjust one or morecharacteristics of the audio signal received and transmitted bymulti-line telephone 110 over one or more of the telephone lines 121 and122. Audio controller 115 independently or collectively adjustsparameters of the incoming and outgoing signal of the telephone lineassociated with the particular audio controller 115. Audio controller115 may take the form of any device including, but not limited to,electrical, mechanical, optical or any the amplitude of the incomingvoice signal delivered to multi-line telephone by that telephone line.For example, audio controller 115 may include an attenuator, anelectrical filter and/or a multiplier. Audio controller 115 may controlany number of audio characteristics including, for example and withoutlimitation, peak volume, average volume, average dB, noise level, bassand treble. Those skilled in the art will appreciate that audiocontroller 115 may incorporate any number of techniques known in the artto adjust any of these and other audio characteristics.

[0018] Multi-line telephone system 105 may incorporate an audiocontroller 115 for each telephone line, as shown in FIG. 1, and/or mayimplement a single master audio controller 115 capable of controllingthe voice signal amplitude of all associated telephone lines. Under thelatter embodiment, single audio controller 115 may include a switch toselect the telephone line for which to control.

[0019]FIG. 2 is a schematic diagram of a multi-line telephone systemimplemented within a communications network in accordance with anotherpreferred embodiment of the present invention. Under this embodiment, acentral office or switch 220 includes one or more audio controllers 215.Under this embodiment, audio controller 215 may be associated with anindividual telephone line or may control audio signal amplitudes of aplurality of telephone lines. Audio controller 115 is preferably stillcontrolled by the telephone customer. Advantageously under thisembodiment, a multi-line telephone having the hardware to practice thepresent invention would not be required, but rather a standardmulti-line telephone would suffice. The audio characteristics of eachtelephone line may be controlled by the user providing control signalsto switch 220. For example, the user may use the telephone keypad, orvoice instructions, to provide instructions to increase or decrease therelative volume of any given telephone line. Alternatively, a localcontroller 217 having a user interface may be provided to generatecontrol signals for audio controller 215. Local controller 217 may be aseparate component coupled between multi-line telephone 110 and switch220 and may optionally be installed within a customer's proprietarynetwork. In yet another embodiment, local controller 217 may be part ofmulti-line telephone 110. ISDN, SS7, proprietary or any other signalingtechnique may be used to deliver control signals from multi-linetelephone 110 or local controller 217 to audio controller 215 of switch220.

[0020]FIG. 4 shows an exemplary user interface 400 of a multi-linetelephone system in accordance with one preferred embodiment of thepresent invention. As shown in this figure, interface 400 is capable ofconnecting to five telephone lines and capable of selectivelyestablishing the connectivity and/or audio characteristics of each line.Interface 400 illustrates a user interface for achieving thefunctionality of the present invention and includes a number of controlsthat are grouped in columns by functionality and in rows according tothe telephone line. Interface 400 includes a telephone line column 410indicating the telephone line. Telephone line column 410 may have adisplay for each telephone line to identify the party or telephonenumber associated with that line. Such a display may be utilized inconjunction with a callerID subscriber service such as is commonlyavailable. An activity column 405 having a light emitting diode(LED)-type device in association with each telephone line may be used toindicate whether a particular telephone line is active. Interface 400 ofFIG. 4 includes another group of columns to selectively monitor andcontrol the signaling received by the user from each of the parties. Asound column 415 having a light emitting diode (LED)-type device inassociation with each telephone line may be used to indicate whether theparty associated with that telephone line is speaking. Sound column 415may also be a bar display and/or may have some memory capability todisplay historical sound characteristics, similar to the horizontal bardisplay that is found in audio equipment such as stereos.

[0021] Advantageously, this memory capability allows the user toidentify the telephone line from which an audio signal originated incase the user happened to look away from the user interface while theaudio signal was being delivered. This feature also allows the user toidentify the source of the audio signal in the event that the user ismonitoring a plurality of telephone lines. An input audio signal column420 similar to that of FIG. 3 (discussed below) may be used toselectively adjust the audio characteristic(s) of each of the incomingtelephone lines. Audio control is preferably implemented with anelectronic control system such that the reset functionality (discussedherein) may be utilized. Further, an input mute column 425 is shown toprevent the signaling from any of the incoming callers from beingreceived by the user. The user may mute a parry by depressing the mutebutton corresponding to the party. When a muted party is talking thesound indicator of sound column 415 would light up such that the user isinformed that the muted party is speaking. The user may then startreceiving signaling from the muted party by depressing again the mutebutton corresponding to the muted party.

[0022] Interface 400 also includes another group of columns toselectively control the output signaling to each of the parties. Anoutput mute column 435 is provided to selectively prevent any signalingto be sent to the corresponding party to the telephone call. Similarly,an output audio signal column 430 selectively adjusts the audioparameters of the signaling to be delivered to the corresponding party.

[0023] A bridge input column 440 is utilized to allow the user tocontrol whether the output of the corresponding party is delivered tothe user via a bridge. If a bridge is not used (preferably the default),the output signal from the corresponding party may be delivered directlyto the user. Otherwise, the output signal is delivered to the bridgewhich combines the signal with the other received signals. A bridgeoutput column 442 is utilized to control whether the output from thebridge is to be delivered to the corresponding party. If the bridge isnot used, the signal from the user is delivered directly to thecorresponding party. Otherwise, the corresponding party receives theoutput signal from the bridge: As preferred, the user may simultaneouslyengage in a bridged call as well as a non-bridged call. Bridging isdiscussed in further detail below. User interface 400 also includes agroup of interfaces to control various overall parameters of thetelephone call. A reset button 445 may be utilized to reset theparameters adjusted in columns 415-435 and buttons 450-460 to theirrespective default values. Interface also includes a group of mastercontrols. A master speaker mute control 455 and speaker volume control453 may be utilized to mute or adjust the volume of the overall signaloutput from the telephone speaker. Further, a master microphone mutecontrol 450 and microphone volume control 447 may be utilized to mute oradjust the volume of the overall signal output from the telephone toeach of the parties to the call. Advantageously, the user may mute oradjust volume without interrupting the settings of each telephone line.An automatic gain control (AGC) 460 may be utilized to automaticallyadjust the relative volumes of each of the incoming and outgoingsignals.

[0024] It is appreciated that any number of user interfaces may beutilized to practice the present invention. For example, in the casewhere more than one bridge is implemented, a user interface in the formof a matrix may be implemented identifying the telephone linesassociated with each bridge. The columns may represent each bridge andthe rows may reflect the telephone lines. Other variations of the matrixmay exist such as for example, where the columns represent input linesand the rows represent output lines. Alternatively, the user interfacemay allow the user to select the bridge to display as to which lines arecoupled to that bridge.

[0025] Advantageously, this embodiment of FIG. 4 provides the user withinterconnectivity control for each active telephone line of a multi-linecall. The features of this embodiment of the present invention may beconceptualized by FIG. 5, which is a schematic illustration of anoverall telephone system connecting a user and one or more callingparties. Telephone system 500 couples a user 501 to one or more parties502-504. The system 500 has a speaker 505 and microphone 510 coupled touser 501 and controlled by master audio controllers 525 and 526(elements 447-455 of FIG. 4) respectively. Controller 525 mixes alllines of bridged calls and/or non-bridged calls. Controller 526distributes the audio output to the bridges and/or to each of thenon-bridged calls. An echo feedback canceler 515 is preferably coupledto audio controllers 525 and 526 and microphone 510 to cancel out anyunwanted echoes and feedback. Bridge 520 couples the user 501 to parties502-504 over telephone system 500. Party 502 is coupled to input audiocontroller 530 a (elements 420 and 425 of FIG. 4) and output audiocontroller 530 b (elements 430 and 435 of 1 FIG. 4) which may disconnect(X), mute (O), attenuate (−), amplify (+) (shown in Figure as ±OX), orotherwise process audio characteristics of the signal in accordance withthe user's settings. Each other party 503 and 504 is coupled to system500 in a similar manner. A bridge 520 is utilized to conference parties502-504 selectively among each other and/or to user 501. Input signalsto bridge 520 are combined into a single output signal to provideselective conferencing between parties 502-504 selectively among eachother and/or user 501. Bridge 520 may be part of the telephone unit, aswitch and/or a third party proprietary device. Presently availablehardware may be utilized to implement the features and functions ofbridge 520. User 501 may selectively establish the type of connectionwith parties 502-504. Particularly, signals from parties 502-504 may bedirectly delivered to user 501 or may be delivered via bridge 520.Similarly, signals to parties 502-504 may be directly delivered toparties 502-504 or may be delivered via bridge 520.

[0026] User 501 may thereby selectively control various call parametersfor each of the called parties using interface 400 of FIG. 4. These callparameters include, but are not limited to, input audio control for eachtelephone line, output audio control for each telephone line, overallvolume control, mute control for each telephone line, and connectioncontrol between one telephone line and the other telephone lines. FIG. 6illustrates one example where party 502 is a secret advisor capable oflistening to the conversation between party 503 and user 501. Party 502may also speak to only user 501. This situation may be implemented bycoupling the output and input of party 503 to bridge 520. Signaling fromparty 502 is directly delivered to user 501. Signaling to party 502 isdelivered from bridge 520. User 501 is coupled to receive signals frombridge 520 and directly from party 502. Output signals from user 501 aredelivered to bridge 520. Party 502 may thereby privately listen to theconversation between user 501 and party 503 and concurrently still speakto user 501 during the call. This call situation may also be establishedwithout bridge 520 as shown in FIG. 7. As shown in FIG. 8, party 502 mayalso be coupled such that it is only privately listening to theconversation between user 501 and party 503. Similarly, as shown in FIG.9, party 502 may also be coupled such that it is only speaking to user501 while user 501 is engaged in a call with party 503. As shown in FIG.10, user 501 may have two simultaneous, non-conferenced calls to parties502 and 503, known as a dispatcher-type function. FIG. 11 shows anexample where user 501 may monitor a plurality of parties 502-504. FIG.12 is an example where user 501 may broadcast a message to a pluralityof parties 502-504. These call situations are merely examples of thenumerous types of call arrangements that may be established with thepresent invention. The bridge may also be implemented within aconnection controller which may be in the form of a microprocessor toprovide the control of the connection parameters to each of the partiesas discussed herein. Other hardware and/or software means may also beimplemented to perform the functions of the bridge.

[0027]FIG. 3 shows another exemplary user interface 300 of a multi-linetelephone system in accordance with another preferred embodiment of thepresent invention. As shown, this user interface 300 is capable ofconnecting to five telephone lines. User interface 300 may beimplemented within the multi-line telephone itself or as a separatecomponent coupling the telephone lines with the multi-line telephone.User interface 300 includes a row of controls for each telephone linecoupled to the telephone. Each row includes a line selection button 305,an audio control 310, and a mute button 315. Line selection button 305preferably allows the user to select which lines are to be conferenced.In accordance with the present invention, audio control 310 allows theuser to selectively adjust the audio signal parameters received by thecorresponding telephone line. Mute button 315 allows the user to mutethe telephone line so that the associated calling party does not receiveany voice signals. Those skilled in the art will appreciate that anynumber of user interfaces could be implemented and are meant to bewithin the spirit and scope of the present invention. For example, inthe implementation of a multi-media conferencing system (such as thatdisclosed in U.S. Pat. No. 5,195,086), the user-interface may be in theform of a Windows-based Graphical User Interface (GUI).

[0028] In yet another embodiment, audio controller 115 of 215 (of FIGS.1 or 2) may be an intelligent controller capable of automaticallyadjusting the relative audio characteristics of the conferenced lines.In this embodiment, intelligent audio controller 115 or 215 may includea digital signal processor (DSP), a microprocessor or other circuitryappropriate to monitor the voice signals of each active line forbackground noise or music. Audio signal parameters of the telephonelines could thereby be adjusted to compensate for the unwanted noise.Additionally, or in the alternative, intelligent audio controller 115 or215 may monitor the voice signals of each active telephone line tocompare various audio characteristics. Intelligent audio controller 115or 215 may thereby automatically adjust the audio signal parameters ofeach telephone lines such that the voice signals have relatively similaraudio characteristics as perceived by the human ear.

[0029] Those skilled in the art will appreciate that the presentinvention may be implemented within any variety of communicationssystems where voice signaling is utilized. For example, the presentinvention may be implemented within any multi-media conferencing systemto selectively control the voice signal amplitude of each of theconferenced callers. An example of such a multi-media system may be thatdisclosed in U.S. Pat. No. 5,195,086 entitled “Multiple Call ControlMethod in a Multimedia Conferencing System” and assigned to AT&T BellLaboratories, incorporated herein by reference.

[0030] The present invention is provided by way of description of oneembodiment. The principles of the invention may be extended to provideselective control of voice signals for any number of telecommunicationsrelated services such as Internet services, television/video/dataconferencing services and the like. The present invention may also beimplemented within a private, local and/or long distance communicationsnetwork. The scope of the invention should only be deemed limited by theclaims which follow.

What I is claimed:
 1. A multi-line telephone system comprising: (a) atleast one coupling means to connect the multi-line telephone system toat least two telephone lines to receive and transmit signals associatedwith each of the telephone lines; (b) a user interface associated withthe multi-line telephone system to allow a user to selectively controlat least one call connection parameter for each of at least two activetelephone lines, wherein the call connection parameter for each activetelephone call is selected from the group consisting of input audiocontrol, output audio control, connection control from a first activetelephone call to a second active telephone call, and connection controlfrom the second active telephone call to the first active telephonecall; and (c) means for selectively controlling a parameter of the callconnection to at least one active telephone call in response to an inputfrom the user interface.
 2. The multi-line telephone system of claim 1,wherein the multi-line telephone system is part of a multimedia systemand at least one telephone call transmits video signals.
 3. Themulti-line telephone system of claim 1 wherein the multi-line telephonesystem is part of a multimedia system and at least one telephone calltransmits video and data signals.
 4. The multi-line telephone system ofclaim 1, wherein the input and output audio controls provide control ofaudio characteristics selected from the group consisting of peak volume,average volume, noise level, bass and treble.
 5. In a multi-linetelephone system, a method of selectively controlling at least one callconnection parameter for each of at least two telephone calls comprisingthe steps of: (a) engaging in a first telephone call with a first partywherein a first call connection parameter is established by themulti-line telephone system; (b) engaging in a second telephone callwith a second party wherein a second call connection parameter isestablished by the multi-line telephone system; (c) connecting the firstand second telephone calls to the multi-line telephone system; and (d)selectively adjusting at least one of the first call connectionparameters, wherein the first call connection parameter is selected fromthe group consisting of input audio control, output audio control,connection control from the first telephone call to the second telephonecall, and connection control from the second telephone call to the 1first telephone call.
 6. The method of claim 5, wherein the input andoutput audio controls provide control of audio characteristics selectedfrom the group consisting of peak volume, average volume, noise level,bass and treble.
 7. The method of claim 5, further comprising the stepof: (e) selectively adjusting at least one of the second call connectionparameter, wherein the first call connection parameter is selected fromthe group consisting of input audio control, output audio control,connection control from the first telephone call to the second telephonecall, and connection control from the second telephone call to the firsttelephone call.
 8. The method of claim 7, wherein the input and outputaudio controls provide control of audio characteristics selected fromthe group consisting of peak volume, average volume, noise level, bassand treble.
 9. A multi-line telephone system comprising: (a) a telephoneline receiver capable of being coupled to at least two telephone callsto receive signals associated with each of the telephone calls, thesignals from each of the telephone calls having a corresponding audiocharacteristic, wherein the audio characteristic is selected from thegroup consisting of peak volume, average volume, noise level, bass andtreble; (b) at least one call connection switch wherein the callconnection switch is associated with at least one telephone calls tocouple the associated telephone call to a user at the multi-linetelephone system; and (c) at least one audio controller capable ofselectively adjusting the audio characteristic of the signal associatedwith at least one of the telephone calls.
 10. The multi-line telephonesystem of claim 9, wherein the audio controller is an intelligent audiocontroller.
 11. The multi-line telephone system of claim 10, wherein theintelligent audio controller includes a microprocessor coupled toreceive and process the signals and wherein the intelligent audiocontroller may responsively adjust the audio characteristic of thesignal associated with at least one of the telephone calls.
 12. Themulti-line telephone system of claim 9, wherein the multi-line telephonesystem is part of a multimedia system and at least one telephone callstransmits video signals.
 13. The multi-line telephone system of claim 9,wherein the multi-line telephone system is part of a multimedia systemand at least one telephone calls transmits video and data signals. 14.In a multi-line telephone system, a method of selectively controlling anaudio level of an incoming audio signal from a telephone call comprisingthe steps of: (a) engaging in a first telephone call with a first parrywherein a first audio signal is received by the multi-line telephonesystem, the first audio signal having a first audio 5 characteristicselected from the group consisting of peak volume, average volume, noiselevel, bass and treble; (b) engaging in a second telephone call with asecond party wherein a second audio signal is received by the multi-linetelephone system, the second audio signal having a second audiocharacteristic selected from the group consisting of peak volume,average volume, noise level, bass and treble; (c) connecting the firstand second telephone calls such that a user at the multi-line telephonesystem may simultaneously receive the first and second audio signalsfrom the first and second telephone calls; and (d) selectively adjustingthe first audio characteristic of the audio signal from the firsttelephone call.
 15. The method of claim 14, further comprising the stepof: (e) selectively adjusting the second audio characteristic of theaudio signal from the second telephone call.
 16. The method of claim 14,wherein the step of selectively adjusting includes the steps ofprocessing at least one of the first and second audio signals andresponsively adjusting at least one of the first and second audiocharacteristics.